Multi-contact electric connectors



May 4, 1965 K. F. BRIDLE 3,182,278

MULTI-CONTACT ELECTRIC CONNECTORS Filed June 18, 1962 A m r Nijl- 32 INveN-roR KlNNa-m F. BRIDLE Amma United States `Patent O 3,182,278 MULTI-CGNTACT ELESTRIC CNNECTORS Kenneth Frederick Bridie, London, England, assignor to Smart 8s Brown (Connectors) Limited, London, England, a company of Great Britain Fiied .inne 18, 1952, Sei'. No. 203,355 Claims priority, appiication Great Britain, Enne 16, 196i, 21,869/61 7 Claims. (Cl. 339-59) This invention relates to multicontact electrical connectors of the plug and socket type and of the general kind comprising a pair of rigid outer shells (usually of metal) adapted to be connected together, each shell enclosing a resilient insert (usually a silicone rubber block) provided with bores which receive the individual contacts.

One desideration or requirement of such a connector is that the individual contacts, together with their respective conductors, should be removable and replaceable to permit replacement of individual conductors and/or contacts, and to permit the contacts to be attached to the respective conductors outside the connector. On the other hand, a further requirement is that the contacts should be iirmly retained in the connector so that they cannot be moved out of position or be inadvertently pulled out in either direction when in use. Another requirement is that the construction should be such that the risk of leakage or flash-over between individual contacts is minimised. Yet another requirement is that there should be no possibility of leakage of gases (e.g., air) or liquids along the conductors to the interior of the connector, even in the event of large and rapid changes in ambient pressure and temperature.

To provide a connector which meets all these requirements is diiiicult, and failures in service are by no means unknown. For example, the most usual arrangement of connector in use at present is one having a silicone rubber forward section supporting the individual contacts, a silicone rubber rear section to guide and seal the cable entry and a center section of rigid synthetic plastics material which carries the individual contacts by means of retention collets. These three pieces are bonded together with adhesive but it is very difficult to ensure a uniform bond and very difficult to inspect the bond. Any imperfection or inclusion in the interfaces presents a probable cause of electrical breakdown. Moreover the retention collets are inaccessible and to release a collet a tool has to be passed through the silicone rubber front section with the risk of damage leading to electrical or sealing breakdown. In another arrangement at present used, there is a single silicone rubber insert having stepped bores to give support and alignment to the cable entry and the individual contacts. The objection to this construction is that the contacts are retained in place only by the elasticity of the silicone rubber which is not wholly satisfactory particularly as the contact retention forces can be adversely' affected by any lubricant contamination and under high temperature conditions. Moreover the sealing can be impaired by angular pull on the cable which will deflect the insert.

It is an object of the present invention to provide a connector which is less liable to failure than are certain types of existing connectors, without undue complication.

A plug or socket multicontact electrical connector part comprises accordingly to the present invention a rigid outer shell, a resilient insert within the shell and provided with bores which receive individual contacts, and rigid retention means behind the insert and spaced from the contacts, each conductor cable having a ferrule firmly secured to it in a region spaced from the contact, at least a part of the contact and at least a part of the conductor 3,l82,278 Patented May 4, 1965 cable between the contact and the ferrule being a snug fit in a bore in the insert and the ferrule being retained against movement in both directions in the retention means.

In this specification and claims the end of the plug or socket connector part which engages the corresponding socket or plug connector part will be considered as the front end and the end through which the `cables enter will be considered as the rear end.

In the construction of the invention, the retention means is out of electrical contact with the contacts and thus the retention means will not provide a leakage path between the contacts. The individual conductor cables are firmly secured but can be easily removed by releasing the ferrules. A further advantage is that an angular pull on the cable is taken directly by the retention means so that sealing will not be impaired.

Each ferrule may be retained by a tubular collet which is retained against movement in at least one axial direction in the retention means. The detailed construction of the ferrule, collet and retention means may take various forms but in one form each ferrule has an end face which engages a rearwardly facing face in the retention means and the collet has a projection or projections which engage a rearwardly facing face on the ferrule. The or each projection on the collet may consist of a forwardly and inwardly extending finger formed, for example, by a tang pressed out of the wall of the collet.

In one form of the invention the retention means comprises two correspondingly perforated plates, the rear surface of the front plate constituting the face engaged by the end face of the ferrule, and the collet has a rearwardly facing face engaging the front face of the rear plate.

In another form using only one retention plate the perforations in the retention plate each accommodates a ferrule which is somewhat smaller than the diameter of the perforation and a tubular collet is provided in the annular gap, iianges or lugs on the collet engaging opposite surfaces of the plate and another flange or lugs engaging a suitable formation on the ferrule, for example an annular groove in the ferrule. One form of collet for this construction rnay consist of a tube having an outward flange at one end to engage a rearwardly facing surface in the retaining plate and a number of fingers each terminating in a T-section at the other end to provide both outward and inward flanges which engage the retaining plate and the ferrule respectively.

In an alternative arrangement, the flanges at the linger tips are omitted, the tips themselves turn outwardly and inwardly alternatively to provide lugs which engage respectively with the forwardly facing surface of the retaining plate and with the groove in the ferrule.

The invention may be performed in various ways and Some examples will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a longitudinal section through the fixed contact part of a plug and socket connector, this part constituting the plug part;

FIGURE 2 is a longitudinal section through the free part of the plug and socket connector, this part constituting the socket part;

FIGURE 3 is an enlarged detailed view of the means retaining an individual conductor cable, and

FIGURE 4 is a view similar to FIGURE 3 showing an alternative arrangement.

Referring now to FIGURE l, the connector part comprises a metal shell 1 having an outer iiange 2 by which the part can be connected to a supporting structure. Fitted within the shell is an insert 3 of resilient silicone rubber, the forward end having a step which engages an inwardly extending flange 4 on the shell. The insert has a number of stepped axial bores each of which carries a metal contact S. The forward ends of the contacts 5 project forwardly from the insert to constitute the individual plug members while the remaining part of each contact is rm- 1y gripped by the insert. The rear end of each contact is secured by crimping or soldering at 6 to the end of the conductor of an insulated conductor cable 7.

Each conductor cable 7 has a ferrule 8 firmly secured to it at a point spaced from the respective contact 5 by a swaging process. At the rear end of the shell 1 is retention means constituted by a front plate 10 and a rear plate 11, the rear plate 11 having a step 12 to provide a rearwardly facing surface 13 which is engaged by a circlip 14 to hold the retention means within the shell and against the rearward end of the insert 3. Each of the plates 1i) and 11 has perforations for each of the conductor cables, the perforations in the rear plate being sufficiently large to permit the passage of annular flanges 15 on the ferrules while the perforations in the front plate are smaller than the flanges. Thus the ferrules are located in a forward direction by the front plate 10. The ferrules are located in a rearward direction by means of collets 16 each of which has an outwardly directed liange 17 which is secured between the plates itl and 11 and has a number of tangs 18 pressed out of its cylindrical wall, the tangs projecting inwardly and forwardly and engaging the rear face of the flange 15 on the ferrule. To release an individual ferrule, a tool may be inserted from the rear of the connector part into the collet to spread the tangs of the collet clear of the flange 15 on the ferrule.

The construction of the socket part shown in FIGURE 2 is similar to that of the plug part shown in FIGURE l, the socket part being provided with a union nut 20 to engage the shell of the plug part. In FIGURE 2 the insert is seen to engage the conductor cables along only part of the length between the contact and the ferrule. However, contact along the entire length as shown in FIGURE 1 may be used.

In the arrangement shown in FIGURE 4, only one retaining plate is employed and the ferrule 31 which grips the cable 32 has an annular groove 33 around its circumference. The aperture in the retaining plate 36 has a rearwardly facing shoulder 34 which is engaged by an outwardly extending flange 35 at the rear end of the collet 36. The collet has a number of axial slits extending from the forward end to near to the rearward end to form a number of the fingers. The forward end of the collet has an outwardly extending flange 37 which engages a forwardly facing shoulder 33 on the retention plate 30 and an inwardly extending flange 39 which engages the circumferential groove 33 in the ferrule 31. To withdraw a ferrule a tool can be inserted from the rear of the connector into the collet to spread the lingers o f the collet clear of the groove 33. In an alternative arrangement similar to that shown in FIGURE 4, the flanges 37 and 39 are omitted and the lingers have their forward ends turned inwardly and outwardly alternately.

The connector has the advantage that the retention of the contact and cable assembly is outside the live electrical areas, and for this reason metal can be used. Moreover leakage is much less likely through the insert.

What I claim as my invention and desire to secure by Letters Patent is:

1. A multi-contact electrical connector part comprising a rigid outer shell, a resilient insert within the shell, a plurality of bores in said insert, Ia plurality of contacts one of which is retained in each of said bores, a plurality of conductor cables one of which is secured to each of said contacts, a first perforated plate in contact with said insert and secured in said shell, a second perforated plate spaced from said first perforated plate and secured in said shell, a ferrule firmly secured to each conductor cable in a region spaced from the respective contact, said ferrule having a surface engaging the surface of said first plate remote from said insert, and a tubular collet for each ferrule, said collet having a face engaging the surface of said second plate facing said insert and having a projection engaging a face on said ferrule facing away from said insert.

2. A connector part as claimed in claim l in which the projection on each collet consists of a linger extending towards the central axis of the collet and towards said insert.

3. A multi-contact electrical connector part comprising a rigid outer shell, a resilient insert within said shell, a plurality of bores in said insert, a plurality of contacts one ot' which is positioned in each of said bores, a plurality of conductor cables one of which is secured to each of said contacts, a perforated plate in contact with said insert and secured in said shell, a ferrule firmly secured to each conductor cable in a region spaced from said contacts, each conductor cable passing through an aperture in said plate and said ferrules being positioned in said apertures said ferrules being smaller in diameter than the apertures in which they are positioned, a collet for each of said ferrules, said collets being positioned in the annular gaps between the walls of said apertures and said ferrules, each collet having flanges engaging opposite surfaces of said plate and having another flange engaging a formation on the respective ferrule.

4. A connector part as claimed in claim 3 in which each collet comprises a tube having an outward flange at one end to engage a surface on said plate facing in a direction away from said insert and a number of lingers each terminating in a T-section at the other end of said collet to provide both outward and inward flanges which engage said retaining plate and said formation on the respective ferrule respectively.

5. A multi-contact electrical connector part comprising a rigid outer shell, a resilient insert within the shell, a plurality of bores in the insert, a plurality of contacts one of which is received in each of the bores, a plurality of conductor cables one of which is secured to each of said contacts, rigid retention means secured to and extending across said shell, separate from said insert and spaced from said contacts, apertures in said retention means through which said conductor cables pass, a plurality of ferrules one of which is secured to each conductor cable in a region spaced from said contacts and is received in the aperture in the retention means through which the cable passes, at least a part of each contact and at least a part of each conductor cable between the respective contact and the respective ferrule being a snug lit in the respective bore in the insert, a tubular collet which surrounds each ferrule in the aperture in which the ferrule is received, cooperating surfaces on said collet and on the retaining means limiting relative movement of said collet and the retaining means in both axial directions and c0- operating surfaces on said collet and the ferrule limiting relative movement of the collet and the ferrule in both axial directions.

6. A multi-contact electrical connector part comprising a rigid outer shell, a resilient insert within the shell, a plurality of bores in the insert, a plurality of contacts one of which is received in each of the bores, a plurality of conductor cables one of which is secured to each of said contacts, rigid retention means secured to and extending across said shell, separate from said insert and spaced from said contacts, apertures in said retention means through which said conductor cables pass, a plurality of ferrules one of which is secured to each conductor cable in a region spaced from said contacts and is received in the aperture in the retention means through which the cable passes, at least a part of each contact and at least a part of each conductor cable between the respective contact and the respective ferrule being a snug fit in the respective bore in the insert, a tubular collet which surrounds each ferrule in the aperture in which the ferrule is received, cooperating surfaces on said collet and said retaining means limiting movement of said collet relative to the retaining means in one axial direction, cooperating surfaces on said collet and said ferrule limiting movement of said ferrule relative to said collet in said one axial direction, .and cooperating surfaces on said ferrule `and the retaining means limiting axial movement of said ferrule relative to the retaining means in the axial direction opposite to said one axial direction.

7. A multi-contact electrical connector part comprising a rigid outer shell, a resilient insert Within the shell, a plurality of bores in the insert, a plurality of contacts one of which is received in each of the bores, a plurality of conductor cables one of which is secured to each of said contacts, rigid retention means secured to and extending across said shell, separate from said insert and spaced from said contacts, apertures in said retention means through which said conductor cables pass, a plurality of ferrules one of which is secured to each conductor cable in a region spaced from said contacts and is received in the aperture in the retention means through which the cable passes, at least a part of each Contact and at least a part of each conductor cable between the respective contact and the respect ferrule being a snug tit in the respective bore in the insert, a tubular collet which surrounds each ferrule in the aperture in which the ferrule is received, cooperating surfaces on said collet and said retaining means limiting movement of said collet relative to the retaining means in one axial direction, cooperating surfaces on said ferrule and said retaining means limiting movement of said ferrule relative to said retaining means in the axial direction opposite to said one axial direction,

and a linger 0n said collet extending towards and at an acute angle to the central axis of the collet and engaging a surface on said ferrule to limit axial movement of said ferrule relative to the collet in said one axial direction.

References Cited bythe Examiner UNITED STATES PATENTS JOSEPH D. SEERS, Primary Examiner.

ALBERT H. KAMPE, Examiner. 

1. A MULTI-CONTACT ELECTRICAL CONNECTOR PART COMPRISING A RIGID OUTER SHELL, A RESILIENT INSERT WITHIN THE SHELL, A PLURALITY OF BORES IN SAID INSERT, A PLURALITY OF CONTACTS ONE OF WHICH IS RETAINED IN EACH OF SAID BORES, A PLURALITY OF CONDUCTOR CABLES ONE OF WHICH IS SECURED TO EACH OF SAID CONTACTS, A FIRST PERFORATED PLATE IN CONTACT WITH SAID INSERT AND SECURED IN SAID SHELL, A SECOND PERFORATED PLATE SPACED FROM SAID FIRST PERFORATED PLATE AND SECURED IN SAID SHELL, A FERRULE FIRMLY SECURED TO EACH CONDUCTOR CABLE IN A REGION SPACED FROM THE RESPECTIVE CONTACT, SAID FERRULE HAVING A SURFACE ENGAGING THE SURFACE OF SAID FIRST PLATE REMOTE FROM SAID INSERT, AND A TUBULAR COLLET FOR EACH FERRULE, SAID COLLET HAVING A FACE ENGAGING THE SURFACE OF SAID SECOND PLATE FACING SAID INSERT AND HAVING A PROJECTION ENGAGING A FACE ON SAID FERRULE FACING AWAY FROM SAID INSERT. 